SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9cf4fea497cdd64b13bff631392b867b8b8d6d3554c8ddad82537d455f7b384' 
  AND token = 'x32a/d/kzrnbJyCJjwHksx66KEWfS1NuEFRhnFh7Tcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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