SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84b1d1ba2da96260e03d09a4928d0292aefeb116fcb36613ece675e1c9d8e366' 
  AND token = 'k7C8IZ9/1QDCvKrs6Ql10JLKq0C32OipHB3WYiyw84I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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