SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55d784dbc88f31913c94d2e404feda8b19a229480950a46dd812f649bfba26b3' 
  AND token = 'CZ4kB08LPrSfdASQdYCdGVNFb5t/oKsxFMfalJ+/H+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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