SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dde9251aec0942eda67383ae094fda42b75b3e37f98d8ba1b04b20ab06cd7238' 
  AND token = '2PQ1UQTY9Lm8WTAMCbPkOXnWdssJyb1JTllMPcuVjWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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