SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e137c2938592f607c7e103ba27871ff0a688c71a9751c072c13a34641e4e2230' 
  AND token = 'iQQ9NZVFQmXIOKbEi7U8eLOoVBG7Xddc49Sl5whn54s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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