SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ed7b01a15fbf66cdfc81805501651db9752fca96db59223acfdf401c91fb4f4f' 
  AND token = '2wMkNWH2QKsuTu6ZrHxhB10hQSTKMjZ/VsmCDE2wOKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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