SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e783e7fc02bd098094d641708e21bc1c7a4ad7e404248ef5fe71ff3a626c80' 
  AND token = '0tDKEZWfT9NXSKDQqGwKz1HtPMoxhXpPqR4AQKm4S1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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