SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed33bdd8121b73b12bdd3d86242db4893f91361215d1eda77bf6bc03e8bf65ea' 
  AND token = 'Q8AGUY0QBIN38KZ9QL8i7yIxK0c+36yyiv9zc0hH+A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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