SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff0e148389051357b28eb90d2f6d0fa8ec34221cbc4907181d9eff13978cb63' 
  AND token = '4f2TwThkSD4FzdoTnT5DJxaOxkhMcYs2yQkSRkKvmVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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