SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2eab6342a7548ec7d7de5901c1bf7d20b5280ffec4bdcae2f30ff857e0b6ddc0' 
  AND token = 'kYA4ZXUKp0ic6/BPe7qUSyDeHl4HuzYph3ofTMRvuMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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