SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49aea09f39ac47c14bec6355c6d75ed04c7e388f86004be5a30318ae3bd25627' 
  AND token = 'sK6RkanzOs4SfIBg4a1hZkb/cJ7iuMIXtTw5Q2DfMVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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