SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54be93d3c010bb2fe42b481d7102169483ada36735694f9fb13989e77273b2dc' 
  AND token = '6JlCl6hdCuGLkTIZf9KZHDgaA9gLYjlpctpKJLGnzGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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