SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a846ef20a81cdf0d2415a258db2f2c520420dca7e650520759d08476f3c98800' 
  AND token = 'Td0o2P+U/frWF2Dt4kbxtudpi1ZjIStIKqPp8RQQTJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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