SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c9e01b7c3b2faff866a81d010359be12bc9df125e5818cd885451ebcc8514d8' 
  AND token = 'G7wCK2OKGNibuyfQhnC8IcbPm5SUp+kfSkNVJREXl/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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