SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d6fdc511a188fdf7816f1dfd4d73923fe85fb8a7ceb9ab0d1bbdf40b655b7d3' 
  AND token = 'rLUJoCvnRK1UsUO7vpynIa8SxoxfPkFqt7Bfe/qXkwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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