SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9326ff310f119118346bdb63452209ae685310525ef39ed8f3fc139a6b688327' 
  AND token = '/7/s/5+s2+/n3V5KImNikSf8ArxZ4Ba2NZsYsBIN1w8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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