SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd14e247558d40ad7d7154abc71886a71d5001bc23e0e84f9c0a0866b91135b56' 
  AND token = 'iePFyuQyD3KBrkaLnI/Ya/xVj3RPZXVjuwpbTgR6XpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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