SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c281977183fbd1748d115fee24bc24e8cc67ba213b12d6ac7bdfba448db39c5' 
  AND token = 'kuoAEqcLhb0fYXSfhRfw7dcsJjt8f5XdNu+S5boQhEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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