SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4546adc0a3f9602d26b83872ad780e0adaa449263380cf3cb160e5390d8287cd' 
  AND token = '0h0DESj8fPsPgwqGeKvGzRYKJCYFmhQBaGyx6amXqTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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