SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe4564575a71c828ecd49c3c05119a0db73f36cf74d8adc3138b600088e7cbc' 
  AND token = 'qupcTgMCZKhU9zL1OYHAWRxDFTnW3gBScVw18jWbRG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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