SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be46180537d8661a60a7abf45ff681372d5f228a941750ac160635712880a317' 
  AND token = 'FmDzS7wvvWHFxrqbiKY2d+1l7w16arUIF3VE8TWFS+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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