SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5846a8c184693084c49251acef353a0eb7ba25164726ec59965d2796e3a19e70' 
  AND token = 'QxYjWCdTtXUxYS7w6qAcZmSMezc2GtRAd0VbSTFZBq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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