SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020c0fcd76fbd842036173bc8815cabcec605323e1ee6c517dc79ddcea87d3db' 
  AND token = 'N1au7xX/fSvkzJDVYRZlBAys1/GeRorR7rTaq85Iqug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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