SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896b74f0acaa580701fd0e21f68408627fad3236245071a6650ce55fde0a5a98' 
  AND token = 'E5IQT7iAxQ3+Jf730cc/ZjrvUolHNm3LWGhgXMzcSXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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