SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e13d7a98fb4b487925f2082bb8aa5712a6b2d68d6936aecce7cc9c3ae2a5ec4' 
  AND token = 'pTpipeDuJyPQD7mccaLOeIDvQuy3kWwtWtau8QKXCxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}