SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '46734a4aa6e72c34fd696fa14e360529108c7a3c3bb0a88b80c138db5b535a3c' 
  AND token = 'RN4Tm6z7MnDYgqHZBVJbrL9WwSYK8cHioUmuI/h4Qts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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