SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '231b91df52f4f3f1ec389b43d22f6a0fe517f5ef36fccc176b489ca2f08bd3c2' 
  AND token = 'N5O1hlGcRBlSUqPI7CDcjSfKTJWDQnj3tbMOYUoOFps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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