SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f0e4c1b67bce8f5f4ea0317fd374a30e23a3a0edf0342981a36bdab87fb71b' 
  AND token = 'p7lkGElYLPtgZMssBBtxq20p5YSgDwJGoxd0ONzoGsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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