SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8768fdaffaa0e2f3b13b28a7d8a89ee823305dfda92054189611d464ec9c4f6e' 
  AND token = 'a/4/JwwHGUVGswqRStVG3dvh0lI6RIqijz881ppWYHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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