SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb826fac2d7b66e9f4bb085b6fe5420eca1d03b9795cf812acd36049f571d3d9' 
  AND token = 'vZ1g4NLKXwrbfCpP3mYORMVkAMR/W9UOrWLh9Fu3uVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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