SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4061a73538a3a7a6e96903e9395edc66ebcad353e1f3c44eda60338a6de773ca' 
  AND token = 'hn3USbLtqr18U2IDsmaCgZMYaLS36+nObooWs1KkV8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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