SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0975ee18b1b86568416a2e6568ea812253d76db21ee5a501ce7b49876a94b29' 
  AND token = 'qLeLC4MwhoHO8fxK1jfEftZ7ilSaXVYiJ/MLqORpz7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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