SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b97d4664c582333a9234fd96f6e22a1005daecb612bbcd79ec71c5d8b72ad4' 
  AND token = 'fNh0HQn/EScJU9KgNslACSqH1F9ssMK87Gszte11MmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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