SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c8c4f0cc91b2038b3206512d6669263d3bf187723156eb851efe5ff507c0c41' 
  AND token = 'Zk9ctXO5pfrB4vB8UOe1klmn6NsjC6br7fk3nMCHSUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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