SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5efdb2647f6fcf190a7220a1e602abf24473356d3fa39b00336f16e3cf18b2eb' 
  AND token = '8f9kZRXNlg4/Tv6T3qC7ji9TF+xRv0RNvSC0CRaJG1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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