SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dbf88afc1c42b32357cffc2d479dfbf9e7356d32342f5fd091e1febb00331b5' 
  AND token = '2/1qwk2goA8dUbrll8XO8N4AJZn1hP9ZdmM/yHrhd34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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