SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6476b52842529eecbd0ea1968d1fceacc8db88f61ec58ceb8cb8a5c25e6c73d' 
  AND token = 'UfVHUW7B0PQoHuLHRJ15JM0qxflvvOD+9kSz2Q3nFUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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