SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af8bba6f96c391d9fb93eb2e527d44c8bcbfcc70b7511844f9fbf31089b39440' 
  AND token = 'pjI4NIFXykn8eB08vmKW+xOH4cP5FJrxdqIicFIU76w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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