SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec912501e70c13245ec6d3eb52c18f0bcfdec4129eb1862e203e2e04c348e5a' 
  AND token = '4QNpAlSJQaXh5OcIbughBK9m1wZaYH1hc/Bo1DpyLww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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