SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185fd641194d27ead9d68638bddfa6c09b67b5f578fb264e8bbc2245d41517e0' 
  AND token = 'f/mW0NUhT+BhxdZ+KCrN5w9MY1/1qNZzEhVRhImpJI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}