SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e202438b7cb72a11f66ffc759064833863c2e6999f5c237ee9a4c873c0360d8' 
  AND token = 'WzPa/1F+igRuYH6ZNUGme3BSyXbs+VDbsnqtj3XN2ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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