SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '865e77e2ca05bca4471a7d033543cc5cf42d1ac7c3f935baa667f2a1a900187f' 
  AND token = '5M1vr0dfozejUAjJqjZkJPnvpY+yGAhxLbEIkzuGkyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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