SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ec673ac187f396755b31d167dfa2d5085a88056c788f707fd12560bf353b3d9' 
  AND token = 'clsQNyrskh6I2/2RVh6fQTS/KLpFgCVWOh6kj2Vu/Dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}