SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8f0ce6896961598d759d52abb783f535efc9d2b801f8ef2d25724e5340c4abd' 
  AND token = 'KIhGfEqzC/jT1JUACBMpmCe7wzJ7idSdyrBEdkDefLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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