SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df9d9b1796b26085f0cd66bf0e350f25733d9d53bb6ea2570071ce38624e9c54' 
  AND token = 'sMdpBBqQClJIlUjsCgb1N/vNnvoBA010HsnONBpxgsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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