SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9fb7000dea5895f21f1e530823951b9b0916b82bd941d4c8044250a364212e8' 
  AND token = 'HsZkkHmCiv8YJgJcq4xnlCFtoL1OtGj7Wei2vUb3wQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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