SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c475a85a5862f20bd718f6897acc3a331ea09ef758a91f8a252117c17cfc472b' 
  AND token = '34BHAM+oVsThQwDq7FrcJiWIHgKM7uCy680FhIAOXY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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