SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a7a80a8f4966adb94bff2e1afb5489dc146356fc75894d798db01056e6764fe' 
  AND token = 'qpg4jaBgV89IoIwf5vESWXIqdjGomhF4+iM/Z1c245U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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