SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03dae31d3ec9ccfb2a7ddff4087ee4bf4ce7aa5c1fab4dc8bf1c70ae052865e8' 
  AND token = '31ybpaqCYb/G3NfSOVkoo0hGKDc/lFW4u/LUOIPIKDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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