SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6575ab2ad0560f9d3b72ac49b44dfd6eb61ce2ccc3601603247c5c6aae355322' 
  AND token = 'uuEld1mMbtTCUATLTxoXvZnVGmwfOUhLiURarCKOeYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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