SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ef02d68335c78af1ccf61404916391ea32e146588f67483d022daf4331306e2' 
  AND token = 'AX5BaYH1o+RzjDIzGbPIaqGj4eOeWE7l9vfiV9CKyOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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