SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a85da55e387fdb5d41533095b119e376173eb4e1879ecb9a73c934d4b63efb19' 
  AND token = '8MtksMobciJjYTlRuFhKihtFoeLHiAzBCLMlHbNrzk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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