SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf767a92049ed4811167a95bae098439aa096610f39d565c35209f9c04180372' 
  AND token = 'ICt7k2gazo/8EPBG8tVEvjBO+wSbHEvtGSvUfqnyAQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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