SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ead2fa9eb90de2a1efb7b7125cfaf81dcc0e82f699a73f4be978e2702c0daf' 
  AND token = 'WclLn02GtyXkayk/gqSKxesUtzRi0QmdCRCpxo+BaLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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