SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd3fc7ef73efe79f5fbe236e31914103b5f6193ab9a164c538503de4d92c4e151' 
  AND token = 'auUvhPD2/x9U2gXwmBnGRpM64arsOa6K2L7zzqoSDZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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