SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f034ae7421dd8858220a713e6156e403727bd7ccf8889644340c9f5634318add' 
  AND token = 'Z+atpaBFso2qvmOWEwp1uBDaAWVZhhrBljGBxolXAQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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