SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ece41b3aa9581788b2ba728a21d185ee2af91ddbdabb4ff65534b6192cc306f' 
  AND token = 'LO718McfRbJI84Z+HTKd2cIqGLVzfkvgB/NDB6GxH9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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