SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff4700052b5888a0fec5c8da2300aae9fccb11637a0f5e5634808583447e62d8' 
  AND token = 'rCI/Xsb1iCUMPYYo9iY6oN6M+POStZwYgsXTvn1kVpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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