SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d2a10387b4492c0b0b571104c9eb71bd5cbbee11d31f2af239ab5d41d87d62' 
  AND token = 'Yvi5zQlFG/8Hl9qmwYmZjzEpQtYE5MAjNc/ZjXGiLFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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