SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7feacf928e2fafdf26859a118097f843d843c054e00756b4df2c78e71f903fd' 
  AND token = 'rd32op8hzfeTtmVfDtAIG0PfNo7BZGjV58wqEPQsDa8=' 
  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"
    }
  }
}