SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcc252bd04eba3277734d1b3e17eef6d2e6481ff5143d8adeaf85ca647b42ccf' 
  AND token = 'CwvslyNjxLFiUNlj3pqc2PErvnqyohxQMOdQNTJS7G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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