SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e42ffa0561770a1b417b3aba8914f846ae4a9d3d889646e2ceaec532dbf1ded' 
  AND token = 'epogBGk/c2lrmFSeFNZzHqe3HtbYsZwcLyXXF+oTy8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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