SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8442fbf5fcfa6fc8cb7683ab47b6de78c2294f6c540a52d395c7906fae58944d' 
  AND token = 'rv2ONPVgaFGveoqcmyTS/B3/6JnxiWPTpm95+TlUJ9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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