SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef158b513143ae75b1bf701b5b2b95f0d8c290f61eb7546892fd5a8683b114d' 
  AND token = 'rc4JzCw4QN0UoUXyT8fhVbtEuegimqC4ig2/vn+nKFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}