SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bd18ea4b438a61be44856b016e46e339f6ebbd3cf14bea113f5de72cd1aa842' 
  AND token = 'ujCxbp7Puw0eYYxOyYvq9TOeLkj2QpvY3nNGQ6phKeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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