SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3ae73fd3fbe26b726cd13b68d108069b39126fdf7b8074880e14f5b37659d77' 
  AND token = 'bsIMKuwP/oabyr84gSjbzCHGmhzQOeUfkfvRlZdAXgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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