SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e79189d932c86d49fd0243af03c3e02dccf8a11f17b61d22558ce92ecedc9a74' 
  AND token = 'XwMc/c+gX71h5QRqpGxDLZ+ACqdGcuNW1S3PyRoPhYw=' 
  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"
    }
  }
}