SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0492279a3365e4a7c0cbb5376c0aaa79f0a1b1858ce45f1f25e805b9c612fd08' 
  AND token = 'ycEvWeKc1VrfNbclKXoAH0zfaSaAgobnpUeO+8N6OP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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