SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e17470a347ff44dc20168f44436e87bd622436a100c9b6b6e30bdd018cdfb1ab' 
  AND token = 'SsJOkJxI1ewOvZhED7c47OnUic0JSKWyT7NLGqN7umY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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