SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a751bfd71e553a245ccd7d883f4bbaa94df30d5cfa9bdc2169d389e8222e982b' 
  AND token = 'rUHmvSqezbEZIlUr27NE2dUniONSZB1HGNaook5ZtwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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