SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6020126a3350f2679012c13e9a1085adee3a0d868140d558ccea05f00256921' 
  AND token = 'iKJFrMDju/SwzYt/UCfacUYyosK/JbvgSsBZZZV2fSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}