SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84586cf23159f5d20a8491b41d46c5967d4b610a1d537bd2d635b9ffda866592' 
  AND token = 'IPvEo+uQLfQM4xvHeujrUOLJLsdCBKQvXGnH0PYAqbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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