SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52eab4ed28a5ddf28ece1aaa27c6d72fa14b01f102c5438eb440fbc75e5e6ce6' 
  AND token = 'ijXEyixiGkn8jxO297sjzKHY61oaJY3PfuDKTMzyqqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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