SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '831d53ed5d7194a4f2d982ded14cc576033a1a475e0dacec0ca72cbea4782689' 
  AND token = 'pJD0hvMsIiA7XaQLUbzQ1ZsExTUv/vpus/SZfCwsoOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}