SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9cb835ef3d68b747b248da59602619feb2677ab7f606e80eb3d109b65439781' 
  AND token = 'm5Xw7rOmkN/XX+asu5yBowZj5Y4KfBJHUKUXbVwyg8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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