SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a55eb105eb03cf2b79189ed2ccbd3285bc1092ef9fb8a892d0d305fee402fe45' 
  AND token = 'MPoDNPXLoJfcJQdfpCfhzWmfE754sIXGWlkpznwPkjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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