SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4cf5ab0e1aa3451042700b2457ca17983e8399eeb0dcd6cadd15da4ea16fc97' 
  AND token = 'RDDroQ1il5zeKaBSSHA1JPaCoiB6r8FXohgcwY5Rsrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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