SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3903aff2756d1a4bd7870500bc0fa1bec06616c2e5f8495b69712845b36d9a9' 
  AND token = '5JmTl23+53rPQzP2Ociszz/RR8a0JkO0BSX2IkkuDxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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