SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '890dc0962fefc403c23470699e2f1939a9a67702fa09d84d38dbd662b92b1457' 
  AND token = '5mF6Jsbv5R0mKrgXlWuL+BpHTJgXqXXF6haSpD8nFDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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