SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fecaaa660a0f1037157fb5d1f4d2504a25ce44beb8ca9ad0a0b0731fa26dc78' 
  AND token = '9eZDKhAi+lZdqIuby/GRjVnCiRG0bBnTmqnNsRlyEkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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