SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '738324794b133ec2f9206af102c1bc1a313f8fea02671c910fcb74891670c28e' 
  AND token = 'sNazBT4zZBAI9UxTkLly/fervJfs/rd6hf9hwQljq5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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