SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0957ac31982bf14d91e6fc3f4d20b15548887385d5211b5723f25f5b68963a4' 
  AND token = 'yPLh5S/luaLAOhmUyv6ZN7MwQn2yQwpdPpJjvKhQ0Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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