SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8b19812970c84ea7677e27ad23bdae9bc15f536b63c08995faa3a80c44f29f4' 
  AND token = 'lHqEY8fD7kEaq8KUrCgpbE2SVCGArGDpgluRMLEZjhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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