SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e0ff0d51a59326e2dfbee3ff51aff63dfb5f28e94ef28ef6d368299170b07a2' 
  AND token = 'cncMYK+EfoI2vrsIbm8JwGbyV3yTyYUGxt6Zq/Uihbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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