SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e39029ccf4ecc60f72c18cadc623f3c892c14b55864447a3babeb1c841b465' 
  AND token = 'juF3Ay+jQiuRoWYL60NNGDyjPE3aq0E0XbctU9R5A20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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