SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99068f37beb52432fa4b1585edf84b11744bbe7dc4d15e98891b5e6c3b20f95f' 
  AND token = 'Espnw+aPUOR0aZN1PhjCuVqOQcZVl9LsYYzHwGb1F1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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