SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '499c526d6c3d26a56331e139d342007b43408f5e6d68aebd9470dc2fca8d0562' 
  AND token = 'DqHufGmUHK7zHwhOw9hgVZVibrll9QJv7v4iaiKSRQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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