SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5fe9099277a74e60f0ccae18bf4692e381f81ac3dd5aae6e27cabdc0b458842' 
  AND token = 'Ep97kkEdoLFfZVfin40EZygN9eNszP83S8LdYc/jyxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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