SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '729192964ebb296fb4a54185ce2d66f4438f327257d57089b5913eaae971391b' 
  AND token = 'DIJNkUB9FBQjHkbTWHv31Ei+p4f3pcip3ue99XeZ258=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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