SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09b55458bb608f8d7fd5c0f1697a7fd44a23191c694473f5ef70aa3914a26e55' 
  AND token = 'EErwLbTgu4/YBEIDgLTtjLwFcjniPsOUw10A+geSfBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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