SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8bb4f1826e4d676dfeae65e45790f9c93bdf14382c01e089c8e7f4df23e51f6' 
  AND token = 'ybzZCO17j0tn6pAZDTuonqWNB6oeA9Iv/0pH+8VVsJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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