SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d2c3fe8cdbb345327f62ce38aca6d979f5e403fa6235044201556c24b4b68a' 
  AND token = 'l6K6gD1/XpHflDYalcPmCbIv6Jh/v/GEqax6qI68yZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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