SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1d36ca09340a7cc2d90599435d527f2422377f1b6463aebadda8ea794ad4f7' 
  AND token = 'RzQOo2Rq80HHGOc6wbLzum1SqCzur75piEeEEQ0pPeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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