SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c81ad1e17e15ed2b03a945bc02318a2dacc4a4cedde46b432a3fed08dac0959' 
  AND token = 'OXLzxtdDanIgtnyKoptFdxW731mYizrk05Q5IiIfiMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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