SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '575fd7eca8278642ce025eb0beb08ebc52d1dce60a22c391772759d42ab149fa' 
  AND token = 'fNAU47UiMx7Vyz7G3wBtFGalHcc0+6Kw8lBk14BgC00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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