SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a24029e8dece3436b59fc8372f86223d87e1852850ae446b189b8c53b484e35d' 
  AND token = 'BQRwNiE/QdsSjuNkvszK5HWc5tHloHf91qDhDZtRbBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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