SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a84b7389975917711193b19d627253136b436cbc0327e3b8b11b32465be8ed11' 
  AND token = 'RmSBmaboGulVvUPPGNfdayX5xtXVS5/AlmiFJer6g2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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