SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e225985556f693c6110e27012e8182d2cede3d6a9394c2002986d812bf4826f0' 
  AND token = '+G8r68Lb3gCfHhWqDdw8brXgtGumrIasuM2htySiCjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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