SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ba43869697a1d540b7bd5889031a964d07821c67183d1947d622423fbd8f7a' 
  AND token = 'eRKJDvRzTDL66ew1pTvdz4EZfVcrT6/cJcN2AXazz4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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