SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f36e954a90852a2c5c72623ee81e2d9965df1a06588b191f9edab0ffb420f2' 
  AND token = 'Gnih6vdUNhbkupqCI8T6w50+X+8AVJKr4IZhEmvsQqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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