SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '962303ad1ed143b8d0eb4b232c8cb301ea24994d6f872f779c3cdb45096254a2' 
  AND token = 'wqPx7V0ciPmyUisdRHp0X1ZqkE9ji5rtChcyFI+Gnxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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