SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdd0ffea478cc4e7022fc52a5d995727f10b3e689967cfe660e2e34375e3ebbe' 
  AND token = 'SdRVMZyCytotZ1MCB2MFo3gYy/OY1XAsajbLVoa2Xgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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